National Taiwan University

Uniband Electronic Corp.

Yun-Hsueh Chuang

Sheng-Lyang Jang

Shao-Hua Lee

Ren-Hong Yen

Shao-Hwa Lee

Chun-Chin Chen

Yi-Chun Lu

Chung-Ching Chiu

A frequency synthesizer of a transceiver for generating a crystal oscillation frequency and a carry frequency having been done a process of frequency offset cancellation with that of another transceiver. The frequency offset cancellation of the frequency synthesizer is done in accordance with a wireless signal which is transmitted from another transceiver received. The frequency synthesizer has a first sigma-delta modulator receiving a signal transmitted by a transceiver at far area responding thereafter a frequency divisor value in accordance with the channel information of the received signal and a frequency offset between two.

Frequency synthesizer with built-in carrier and crystal oscillation frequency offset cancellation

A multi-phase voltage-control oscillator including a first voltage-control oscillator circuit and a second voltage-control oscillator circuit is provided. The second voltage-control oscillator circuit and the first voltage-control oscillator circuit have a plurality of inductors, and the inductors in the second voltage-control oscillator circuit are respectively cross-coupled with the inductors in the first voltage-control oscillator circuit to generate a mutual inductance effect, so as to output a plurality of oscillating signals with different phases.

Multi-phase voltage-control oscillator

An injection-locked frequency divider includes a ring oscillator, a signal injection circuit, a first adjustable load circuit and a second adjustable load circuit. The ring oscillator generates an oscillation signal according to a differential signal outputted by the signal injection circuit. According to an adjustable voltage, the first and second adjustable load circuits can respectively change equivalent impedances of the first adjustable load circuit and the second adjustable load circuit so that a free-running frequency of the oscillation signal of the ring oscillator is adjusted and an injection-locked frequency range of the injection-locked frequency divider is expanded.

Injection-locked frequency divider

An injection-locked frequency divider is provided. The injection-locked frequency divider includes a variable reactance unit, a signal injection unit, a first switch, a second switch, a first transformer, and a second transformer. The variable reactance unit, the first switch, the second switch, the first transformer, and the second transformer form a transformer-based LC-tank oscillator. The signal injection unit receives an injection signal. When the injection-locked frequency divider is in a locked state, the transformer-based LC-tank oscillator outputs a frequency division signal. Employing the feedback action of the first transformer and the second transformer, the present invention not only has a wide locking range but also promotes the realization of the low operating voltage.

A multi-phase voltage-control oscillator including a first voltage-control oscillator circuit and a second voltage-control oscillator circuit is provided. The first voltage-control oscillator circuit includes a first LC tank and a first inductor assembly unit. The second voltage-control oscillator circuit includes a second LC tank and a second inductor assembly unit. A mutual inductance effect is generated between the inductors of the first voltage-control oscillator and the inductors of the second voltage-control oscillator.

A voltage control oscillator (VCO) includes a VCO circuit and a back-gate coupling circuit, wherein the VCO circuit includes at least a first transistor, a second transistor and a resonant cavity formed by an inductor and a capacitor. The back-gate coupling circuit is formed by a plurality of capacitors and a plurality of resistors. In the embodiments of the present invention, the capacitors are coupled to the back-gate terminals of the first transistor and the second transistor, so as to reduce the power consumption and the phase noise of the VCO.

Back-gate coupling voltage control oscillator

An injection locked frequency divider includes a signal injection unit, a Hartley voltage controlled oscillator and a biasing unit. The signal injection unit and the biasing unit output an injection signal to the Hartley voltage controlled oscillator to bias the Hartley voltage controlled oscillator. The Hartley voltage controlled oscillator, which includes a first transistor, a second transistor and a LC tank, receives the injection signal and outputs a differential output signal through a first output terminal and a second output terminal. First terminals of the first and second transistors are respectively coupled to the first and second output terminals, and second terminals of the first and second transistors are coupled to a first node. The LC tank decides a resonant frequency of the Hartley voltage controlled oscillator and serves as a positive feedback circuit for the first and second transistors.

Growing community of inventors

Taoyuan County, Taiwan

Yun-Hsueh Chuang